Auditorium



1 1 E. MILKUTAT 1,737,666

AUDITORIUM Filed Sept. 8; 1925 5 Sheets-Sheet l Dec. 3, 1929.-

E. MILKUTAT AUDITORIUM Filed Sept. v 1925 5 Sheets-Sheet 2 Fig.8.

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Patented Dec. 3, 1929 PATENT OFFICE ERNST MILKUTAT, 0F TILSIT, GERMANY:

AUDITORIUM Application filed September 8, 1925, Serial No. 55,044, andin Germany April 8, 1925.

My invention relates to a method of constructing rooms to insure goodacoustic effects, and it is an object of my invention to so constructrooms for concerts, theatrical and other performances, lectures, etc.,that the sounds produced are heard to full effect.

To this end, I proportion such rooms to the golden rule of proportionand construct them with a ceiling of hyperboloid shape.

It is well known that musical and other performances, lectures and thelike, are often much impaired by bad acoustic conditions, by deadeningof sounds, resounding, etc. The attempts made heretofore to improve suchpoor conditions were more or less of a tentative character, though basedon the experience of years.

These drawbacks are overcome by my invention which enables the effect ofsound to be increased and opens up quite new prospects-in thearchitecture of rooms of the kind described.

It establishes a new rule by which rooms having good acoustic conditionsmay be constructed regardless of size. It shows the connection of causeand effect and so enables not only new rooms to be designed on theseprinciples but also enables existing ones to be tested for theiracoustic properties.

Obviously, conditions which bring about a more rapid reflection of soundand eliminate resounding, for instance, polished wainscotting, willfavorably influence the acoustic conditions of a room, but such detailsare secondary to the fundamental principle of proportion aslaid down bymy invention.

In the drawings, the application of my novel method is illustrated byway of example.

Fig. 1 is a diagram of the golden rule of proportion or golden section.

Figs. 2 to 8 are diagrams showing the paths of sound waves in paralleltoa wall,

Fig. .9 is a diagram showing the influence of a disturbing element inthe path of the waves,

Figs. 10 and 11 illustrate the arching of the ceiling of a roomconstructed in accordance with my invention,

Fig. 12 is a plan view of a concert room in accordance with myinvention, with a room for the band,

Fig. 13 shows the path of the sound waves as it will be under theinfluence of the arch in Fig. 10.

Referring now to Fig. 1, the line a will be divided on the golden ruleof proportion if the larger section b is the geometric mean of theentire line a and the other section (a-b).

To effect such division graphically, erect a vertical on the line a-inone of its end points, B, make this vertical BC equal to one half I theline a, draw a circle about C with the radius CB, connect A and C anddraw another circle about A with a radius equal to the distance from Ato the point of intersection with the first circle of the line AC, thispoint being indicated by D. The intersection of the circle AD with theline a, G, is the point of division on the golden section.

Now, b is to (ab) as a is to Z), or, expressed as an equation,

he length of the larger section is and the length of the shorter sectionis These equations are established as follows:

By forming the quadratic completion to the equation b +aba =0, thefollowing is obtained:

and, by adding both sides of the equation, the result will be bymultiplying with 4 from which extracting g,

If constructing a room from these data, so that a is its length, b isits width, and (a-b) is its height, it will be found that its acousticconditions are very good.

This is based on several causes the most important of which is the veryregular distribution of the waves or systems of Waves in space so thatthroughout the room and even in its smallest part the frequencies andintensities of the sound are substantially equal and no particular typeof sound is accumulated or separated anywhere in said room. Anothercause is the fact that a system of waves emitted from any point of theroom in any direction, is, after comparatively few reflections, ascompared with other rooms, directed into the corners of the room orreturned to the origin, the sound emitting body.

Figs. 2 and 3 illustrate wave systems extending in parallel to the wallsand having a reflection angle of 45 degrees. The cause I is thecontinuous reflection of the waves by the walls because said walls arein a steady constant ratio to each other.

As the proportion is a constant one, the same law also applies when thewall has the length a and the width (a-b) or 2ba.

Figs. 4 and 5 illustrate systems of waves extending in parallel to thewalls for the first case in which the length is a and the width (ab).Figs. 6, 7 and 8 show that this applies to any angle of reflection.

A disturbing body in the way of the waves does not destroy this acousticbehavior. On the contrary, it will often even reduce the length of thewave routes, as shown in Fig. 9.

Considering now the routes of the waves, for instance, in Figs. 4 and 5,as projections of the wave routes on the walls of the resonator, thesame will apply to the route as to its projection.

Another cause of the good acoustic conditions is that withsuperimposition of waves for the same sound, amplitudes of equal, viz,double, and therefore, maximum length are formed, which are uniformlydecreased by reflection. The resulting energy I from the two interferingoscillations is equal to four times the single energy, if the energiesof the interfering oscillations are equal, because the energy is priportional to the square of the amplitude. his also applies toovertones.

Such a room has a high sound capacity even for very high sounds emittingshort waves.

To prevent the reflection coeflicient in the resonator from becoming toohi h, it is possible to reduce said coeflicient %y a specialconstruction of the ceiling, that is, intensifying the sound. Thisrequires arching of the ceiling of the resonator. A ceiling constructedin accordance with my invention is shown in Figs. 10 and 11 Fig. 10 is across section of the room. The hyperboloid arch is constructed bysuitable means, for instance, from evolvents, by dividing the height ofthe room into two halves and dividing the upper half into n equal parts.

Similarly, the length of the ceiling is divided into halves, each halfbeing subdivided into n equal parts.

Said verticals are erected on the points where the lines are tangent tothe curve. In this manner, a hyperbola is obtained, 0 being the factorof proportionality. This hyperbola can be used from b =%y 2112b, to m =ad yn 5 Or,1fa

' b 10, 37 :1 l :1 to d ab 2ba a b I a-b but also the indirectly steadyrelation of and and so on.

Fig. 13 shows the route of the waves under the influence of the arch inFig. 10. The principle of steadiness of wall lengths applies to allrooms including those that have more than six plane walls.

As an example of a room with band stand, Fig. 12 is given. Here, a isthe length, l) the width, (ab) the height of the room. The length of theband stand (or' stage) is (a 6), its width being (2ba), and being shapediike Fig. 10 in plan View.

In a specific case; given the length of the hall or room, for example100 feet, the other dimensions of the hall could be computed as follows:i

The arm A0 of the triangle, see Fig. 1 being 100, and the arm B0 being%or 50, the hypotenuse A0 would be 111.8+. The distance AD would beA0DU=AU 0B=111.8+ 50=61.8+. The line AD being the same length as AG, thedistance Z) 61.8+. The distance GB a b 100 61.8 38.2. The dimensions ofthe room then are: length 100 feet, width 618+ and maximum height 38.2-.In the same manner lb-a 1236+ 100=23.6+, etc. It will be seen that thesedimensions 100, 61.8+38.2 and 235+ bear a constant relation to eachother. It will be obvious that the dimensions of any size room can becomputed by this method.

I claim:

1. An improved concert hall or the like which consists in a room thenumerical values of the dimensions of the length, breadth and maximumheight of which form a mathematical series formed according to thegolden rule of proportion, which comprises a series in which each termis the mean proportional of the terms which precede and follow itrespectively and in which the ceiling of the room is hyperboloidal inform to avoid obliterations of sound.

2. An improved concert hall or the like which consists in a hall thenumerical values of the dimensions of the length, breadth and maximumheight of which form a mathematical series formed according tothe goldenrule of proportion, which comprises a series in which each term is themean proportional of the terms which precede and follow it respectively.

3. An improved concert hall or the like which consists in a room thenumerical values of the dimensions of the length, breadth and maximumheight of which form a mathematical series in which each term is themean proportional of the terms which immediately precede and follow itrespectively and in which the ceiling of the room is formed according totwo hyperbolae the asymptotes of which intersect on a line passingvertically through the center of the ceiling and the limbs of saidhyperbolae meeting at one end of the center of the ceiling and at theother end joining with walls parallelly disposed so as to maintain thesymmetry of the shape of the room.

4. An improved concert hall or the like which consists in a room thenumerical values of the dimensions of the length, breadth and maximumheight of which form a mathematical series in which each term is themean proportional of the terms which immediately precede and follow itrespectively and in which the ceiling of the room is formed according totwo hyperbolee the asymptotes of which intersect on a line passingvertically through the center of the ceiling and the limbs of saidhyperbolae meeting at one end at the center of the ceiling and at theother end joining with walls parallelly disposed so as to maintain thesymmetry of the shape of the room, there being an orchestra space builton to the concert hall proper having the shape and dimension ratio ofthe large hall while the hyberbolic interior formation is used on theside of the orchestra space facing towards the concert hall.

In testimony whereof, I have signed my name to this specification.

ERNST MILKUTAT.

